# 利用str函数

def atoi(s):

num = 0

for i in s:

for j in range(10):

if i == str(j):

num = num*10 + j

return num

# 利用ord函数

def atoi1(s):

num = 0

for i in s:

num = num*10 + ord(i) - ord('0')

return num

# 利用eval函数

def atoi2(s):

num = 0

for i in s:

t = "%s * 1 " %i

n = eval(t)

num = num * 10 + n

return num

# 利用reduce函数

from functools import reduce

def atoi3(s):

return reduce(lambda num, i: num * 10 + ord(i) - ord('0'), s , 0)

if __name__ == '__main__':

s = "432"

#print(type(s))

#s = input ("please input: ")

print(atoi2(s))